LeetCode ||Insertion Sort List

最新推荐文章于 2024-11-10 21:15:35 发布

原创最新推荐文章于 2024-11-10 21:15:35 发布 · 306 阅读

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#插入排序 #LeetCode #Insertion Sort #List

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本文介绍了一种使用插入排序算法对单链表进行排序的方法，包括算法实现和步骤解释。

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
public:
    ListNode* insertionSortList(ListNode* head) {
        
        if(head == NULL || head->next == NULL) 
            return head;
            
        ListNode* newHead = head;
        
        
        ListNode* hi = head->next;
        ListNode* hiPre = head;
        ListNode* hj = head;
        ListNode* pre = NULL;
        while(hi != NULL)
        {
            while(hj != NULL && hj != hi && hj->val <= hi->val)
            {
                pre = hj;
                hj = hj->next;
            }
            
            if(hj == NULL)
                break;
                
            if(hj == hi)
            {
                hiPre = hi;
                hi = hi->next;
            }
            else if(pre == NULL)
            { 
                
                //delete
                hiPre->next = hiPre->next->next;
                
                //insert
                ListNode* tmp = newHead;
                newHead = hi;
                newHead->next = tmp;
                
                hi = hiPre->next;
            }
            else
            {
                //delete
                hiPre->next = hiPre->next->next;
                
                ListNode* tmp = pre;
                pre->next = hi;
                hi->next = hj;
                
                hi = hiPre->next;
            }
            
            hj = newHead;
            pre = NULL;
        }
        
        return newHead;
    }
};